net/virtio: fix variable assignment in helper macro
net/virtio: fix variable assignment in helper macro

Inside Macro ASSIGN_UNLESS_EQUAL(var, val), assignment to var is always
failing as assignment done using var_ having local scope only.
This leads to TX packets not going out and found broken due to cleanup
malfunctioning. This patch fixes the wrong variable assignment.

Fixes: 57f90f894588 ("net/virtio: reuse packed ring functions")
Cc: stable@dpdk.org

Signed-off-by: Vipul Ashri <844c38eb0d72ef7b4a437d9ce0e9eab45853bf39@oracle.com>
Acked-by: Andrew Rybchenko <ac94ab2a8fe9a9a087f6e24dcbc16626b52c07e8@solarflare.com>
Reviewed-by: Maxime Coquelin <9a2667dee3b90866bbc9c2696cff2b7d5616c95a@redhat.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk